The water system for a city consists of water storage tanks, pumping stations, and a network of pipes to distribute the water to residents. A properly constructed network of water distribution pipes will have valves at all critical locations in the network such that portions of the network can be shut down for service without affecting water service to the balance of the city. The pipes which make up the water distribution system range in size from as small as three or four inches in diameter to as large as two feet in diameter, and the valves for controlling the flow of water through the system have similar ranges of sizes. Also, most municipal underground water systems have been developed over a period of over fifty years-and incorporate valves from a number of manufacturers.
A water system may have hundreds or thousands of valves, each of which is unique in that each valve has its own operating characteristics. For example, to move a valve from the fully closed position to the fully open position will involve turning the stem of the valve a finite number of revolutions in either the clockwise or counterclockwise direction. The normal operation of the system may require that the valve remain open, and closed only when repairs are being made in adjacent pipes. On the other hand, if the valve regulates a backup fluid system, the valve may be normally closed during proper operation of the system. Each valve is also designed to withstand a given maximum torque, and the application of excessive torque to a valve will cause damage. The moving parts of the valves in the system are also positioned below the ground level and are subjected to constant humidity, heat, cold, wear, and contaminants such that the working parts gradually deteriorate. A valve that has not been exercised for a substantial period of time will also frequently be "frozen" and an operator must jar the valve stem loose without damaging the valve before it can be exercised. Particles of soot, worn metal, and rust also accumulate on the parts such that the valve stem may bind and lock up before it reaches a fully open or fully closed position.
Valve operating machines are available which have hydraulic motors for rotating an elongate key which extends through a shaft to attach to the valve stem of the valve and open and close the valve. Such hydraulically operated valve controlling machines, however, are capable of applying an excessive amount of torque to a valve stem. The operators of such machines must avoid forcing a valve beyond its maximum number of revolutions or applying excess torque to a valve which has become locked up before it has reached the fully opened or fully closed condition.
U.S. Pat. No. 5,381,996 discloses a hydraulically driven valve operating machine which is controlled by a computer. This machine requires that the operator insert into the computer the parameters of the valve to be operated before initiating the exercise, and the programmed machine will carry out an exercise which does not exceed the parameters of the valve.
It is not uncommon to exercise 10 to 20 valves of a municipal water system during the course of a single day, and it is critical for the proper operation of the system that accurate records of all the valves of the system be maintained. Currently, a municipality assigns a number to each of its valves and retains the information for each valve in a card catalog or computer. The record includes information regarding the last operation of the valve, and a technician who is instructed to exercise a given valve must first obtain a copy of the records pertaining to the valve to be operated. At the valve site, the technician will connect the valve operating machine to the valve stem and input the necessary parameters into the computer after which the valve will be exercised. Thereafter, on his return to the central office, the technician will update the records of all the valves he has exercised so that they will be current for the next operation thereof.
The technician using the machine of U.S. Pat. No. 5,381,996 will consume a significant amount of time in obtaining the records of valves to be operated, inputting the parameters from those records into the computer of the machine, and then updating the records of the municipality after the exercise thereof is completed. It would be desirable to provide a system for controlling an underground fluid flow system without requiring a technician to manually load pertinent information into a valve operating machine and to manually update the records of a municipality after the exercises have been completed.